Abstract:Based on Patir and Cheng’s average flow equation and flow factor,considered the factors such as surface profile and elastic deformation,the lubrication analysis model of main bearings of engine was established based on the fluid lubrication theory.The influences of the surface profile of journal and bearing bush on the lubrication performances of main bearings were analyzed,including the minimum oil film thickness,the peak oil film pressure,the total friction power loss and peak asperity contact pressure.The results show that the roughness size and roughness texture direction of journal and bearing bush have significant influence on the lubrication performances of main bearings.As the roughness value increases,the minimum oil film thickness is increased,the oil film pressure is decreased,the peak asperity contact pressure and total friction power loss are increased.Compared with transverse texture and isotropy,longitudinal texture is helpful to increase the minimum oil film thickness and reduce the total friction power loss and peak asperity contact pressure.When the value of the roughness is constant,the peak asperity contact pressure and the asperity friction power loss will increased with the increase of internal combustion engine speed and explosion pressure,which will lead to the increase of wear and the decrease of engine efficiency .